1. Field of the Invention
The present invention relates to devices for applying high magnitudes of torque to lug nuts of the type that may be employed to secure wheels to the hubs of large trucks or heavy equipment.
2. Description of the Prior Art
It has long been recognized that lug nuts employed to mount large wheels on trucks and heavy equipment require application of high torque often exceeding that which may be applied by conventional wheel wrenches or prior art manual torque devices. Often times a truck driver or heavy equipment operator will be faced with the task of removing a wheel from a vehicle or track from a tracked vehicle without the ready availability of exotic torque applying devices. Frequently, the operator is faced alone with this task without readily available assistance. Since prior art devices have typically proven inadequate to enable a sole workman to apply sufficient force to remove the mounting lug nuts, valuable time is lost in making the necessary tire change and schedules typically disrupted, not only for the directly involved operator and vehicle, but for other equipment and personnel dedicated to a common project. Experience has proven that substantial time, money and convenience could be realized if an economical and reliable lug apparatus were available which would afford sufficient torque for loosening of even the most secure lug nut. Trucks and heavy equipment, being exposed to heavy loads and frequently rugged terrain, require that the lug nuts be tightened to a high torque. This, coupled with the fact that during use the nuts may be exposed to corrosive environmental conditions and sometimes damage, leads to the fact that high torque is frequently required for removal often on the order of thousand foot pounds.
In recognition of the serious problem confronting operators faced with the task of removing such lug nuts, numerous efforts have been made to provide a device which is economical to manufacture and which will supply sufficient mechanical advantage to develop the required torque under typical field conditions. One such device is shown in U.S. Pat. No. 3,158,050 to Shandel. That patent depicts a manual impact wrench having a torque shaft including a socket on one end and having the medial portion thereof telescoped horizontally through a fitting supported from an upright jack stand. Mounted on the remote end of such torque shaft is a cross bar incorporating a pair of diametrically opposed stubs. A double ended impact hammer bar is rotatably received over the end of the shaft to be received between such stubs for rotation relative to the shaft to impact the stubs and apply impact to the torque shaft. Such a device, while adequate for use with passenger car vehicles and the like, has restricted application since the double ended impact bar is of limited length thus limiting the amount of torque which may be applied to the torque shaft. Furthermore, the innerengagement between the impact bar and cross bar is not a positive engagement, thus leaving open the possibility of disengagement under use resulting in injury to the operator and probable damage to the tool itself.
Other efforts have led to lug nut removing devices incorporating a vertical stand having telescoped thereonto a fitting which may be adjusted to selected heights and incorporating a horizontally projecting head receivable in a socket formed on one end of a torque shaft, the opposite end of such torque shaft carrying a lug nut socket. Mounted medially on the torque shaft is a ratchet wheel driven by a lever arm. A device of this type is shown in U.S. Pat. No. 3,095,945 to Shandel. Such an arrangement, while adequate for use in removing lug nuts which have not been excessively tightened, is limited by the fact that under use the stand is loaded on one side and that the coupling with the torque shaft is such that there exists a great danger that the shaft will become uncoupled during use thus resulting in injury to the operator and damage to the device itself and also disfigurement of the lug nut as disengagement under force takes place. Additionally, the use of presently known economical ratchet mechanisms severely limits the magnitude of torque which may be applied.
Other efforts to solve this problem have led to the proposal of torque shafts for bridging between a lug nut and an upright stand, wherein the coupling between the stand and upright is made by a joint and socket connection. A device of this is shown in U.S. Pat. No. 3,097,550 to Johnston. Again, Johnston's arrangement, while being satisfactory for some low torque applications, is limited by the fact that the load is carried on one side of the stand and the lever arm handle can only be engaged with the torque shaft from only two diametrically opposite positions relative to the torque shaft.